My favorite artist is Irishman Harry Clarke. Illustrator and stained glass artist extraordinaire. Died young in the early 20th century- probably from heath complications from decades of using acid to etch glass. He had a creepy streak as well and was famous for illustrating for Edgar Allen Poe.

This first one is not a painting... it is made by layering acid-etched glass...

I'm actually with you Tiki on the Escher. Definitely ranks up in my top tier as well. I've always admired his ability to temper his technical and mathematics skills with true visionary artistic concepts. Pretty hard to wrap your mind around how his mind worked.

I've always wanted to take Escher's piece "Three Worlds" and execute it in stained glass a'la Harry Clarke using 3 layers of etched and sandblasted and painted glass stacked on top of each other. It's been on my back burner for years. Maybe I'll dig it out again.

Remedios Varo was born in Spain, spent her young adult years in France (in the company of the usual surrealist suspects), and eventually move to Mexico, where she did most of her work. She died there in 1963 (at the far-too-young age of 53). Here's just one sample of her painting